On 5/20/20 4:56 AM, Ming Lei wrote:
> During waiting for in-flight IO completion in reset handler, timeout
> or controller failure still may happen, then the controller is deleted
> and all inflight IOs are failed. This way is too violent.
>
> Improve the reset handling by replacing nvme_wait_freeze with query
> & check controller. If all ns queues are frozen, the controller is reset
> successfully, otherwise check and see if the controller has been disabled.
> If yes, break from the current recovery and schedule a fresh new reset.
>
> This way avoids to failing IO & removing controller unnecessarily.
>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
> Cc: Keith Busch <kbusch@xxxxxxxxxx>
> Cc: Max Gurtovoy <maxg@xxxxxxxxxxxx>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> drivers/nvme/host/pci.c | 37 ++++++++++++++++++++++++++++++-------
> 1 file changed, 30 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index ce0d1e79467a..b5aeed33a634 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -24,6 +24,7 @@
> #include <linux/io-64-nonatomic-lo-hi.h>
> #include <linux/sed-opal.h>
> #include <linux/pci-p2pdma.h>
> +#include <linux/delay.h>
>
> #include "trace.h"
> #include "nvme.h"
> @@ -1235,9 +1236,6 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
> * shutdown, so we return BLK_EH_DONE.
> */
> switch (dev->ctrl.state) {
> - case NVME_CTRL_CONNECTING:
> - nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING);
> - /* fall through */
> case NVME_CTRL_DELETING:
> dev_warn_ratelimited(dev->ctrl.device,
> "I/O %d QID %d timeout, disable controller\n",
> @@ -2393,7 +2391,8 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
> u32 csts = readl(dev->bar + NVME_REG_CSTS);
>
> if (dev->ctrl.state == NVME_CTRL_LIVE ||
> - dev->ctrl.state == NVME_CTRL_RESETTING) {
> + dev->ctrl.state == NVME_CTRL_RESETTING ||
> + dev->ctrl.state == NVME_CTRL_CONNECTING) {
> freeze = true;
> nvme_start_freeze(&dev->ctrl);
> }
> @@ -2504,12 +2503,29 @@ static void nvme_remove_dead_ctrl(struct nvme_dev *dev)
> nvme_put_ctrl(&dev->ctrl);
> }
>
> +static bool nvme_wait_freeze_and_check(struct nvme_dev *dev)
> +{
> + bool frozen;
> +
> + while (true) {
> + frozen = nvme_frozen(&dev->ctrl);
> + if (frozen)
> + break;
> + if (!dev->online_queues)
> + break;
> + msleep(5);
> + }
> +
> + return frozen;
> +}
> +
> static void nvme_reset_work(struct work_struct *work)
> {
> struct nvme_dev *dev =
> container_of(work, struct nvme_dev, ctrl.reset_work);
> bool was_suspend = !!(dev->ctrl.ctrl_config & NVME_CC_SHN_NORMAL);
> int result;
> + bool reset_done = true;
>
> if (WARN_ON(dev->ctrl.state != NVME_CTRL_RESETTING)) {
> result = -ENODEV;
> @@ -2606,8 +2622,9 @@ static void nvme_reset_work(struct work_struct *work)
> nvme_free_tagset(dev);
> } else {
> nvme_start_queues(&dev->ctrl);
> - nvme_wait_freeze(&dev->ctrl);
> - nvme_dev_add(dev);
> + reset_done = nvme_wait_freeze_and_check(dev);
Once we arrive at here, it indicates "dev->online_queues >= 2".
2601 if (dev->online_queues < 2) {
2602 dev_warn(dev->ctrl.device, "IO queues not created\n");
2603 nvme_kill_queues(&dev->ctrl);
2604 nvme_remove_namespaces(&dev->ctrl);
2605 nvme_free_tagset(dev);
2606 } else {
2607 nvme_start_queues(&dev->ctrl);
2608 nvme_wait_freeze(&dev->ctrl);
2609 nvme_dev_add(dev);
2610 nvme_unfreeze(&dev->ctrl);
2611 }
Is there any reason to check "if (!dev->online_queues)" in
nvme_wait_freeze_and_check()?
Thank you very much!
Dongli Zhang
> + if (reset_done)
> + nvme_dev_add(dev);
> nvme_unfreeze(&dev->ctrl);
> }
>
> @@ -2622,7 +2639,13 @@ static void nvme_reset_work(struct work_struct *work)
> goto out;
> }
>
> - nvme_start_ctrl(&dev->ctrl);
> + /* New error happens during reset, so schedule a new reset */
> + if (!reset_done) {
> + dev_warn(dev->ctrl.device, "new error during reset\n");
> + nvme_reset_ctrl(&dev->ctrl);
> + } else {
> + nvme_start_ctrl(&dev->ctrl);
> + }
> return;
>
> out_unlock:
>
